Discovery

The Oracle Communications Session Border Controller, acting as a P-CSCF, can discover remote S-CSCFs using Service-Route header that returns with a 200 OK response from the registrar for a REGISTER request from the endpoint. The system takes the top Service Route from the response and uses it as the first hop in the egress route for the endpoint. Because the creation of dynamic session agents is based on the Service Route returned in the 200 OK, there is no impact to handling AoRs with multiple contacts.

In addition, the system stores the Service Route header data with the endpoint’s registration cache. If the Service Route is an FQDN, a DNS look-up is used to provide the route to the S-CSCF.